超磁歪アクチュエータを用いた平面スピーカーの磁場・構造・音場の達成解析手法に関する研究

摘要

In this study, a coupled analysis method for flat panel speakers driven by giant magnetostrictive material (GMM) based actuator was developed. The sound field produced by a flat panel speaker that is driven by a GMM actuator depends on the vibration of the flat panel, this vibration is a result of magnetostriction property of the GMM. In this case, to predict the sound pressure level (SPL) in the audio-frequency range, it is necessary to take into account not only the magnetostriction property of the GMM but also the effect of eddy current and the vibration characteristics of the actuator and the flat panel. In this paper, a coupled electromagnetic-structural-acoustic analysis method is presented; this method was developed by using the finite element method (FEM). This analysis method is used to predict the performance of a flat panel speaker in the audio-frequency range. The validity of the analysis method is verified by comparing with the measurement results of a prototype speaker.%本稿では，超磁歪アクチュエータを用いた平面スピーカー の音庄レベルを予測するために，磁界・構造・音場の達成 解析手法を提案し，実測との比較検証を行った。 　また，有限要素法を用いた周波数領域での磁界解析にお いて，バイアス磁界印加時における超磁歪素子の磁歪現象 を計算するためのシンプルでありながら精度の高い解析手 法を提案した。